Smoking is prohibited in many locations where smokers may spend considerable time, including work places, restaurants, airplanes, and hospitals. In such settings, the experience of craving for cigarettes can cause significant discomfort and distraction. Nicotine absorption into the bloodstream and brain is a factor, but it is not the only or primary factor for relief of cigarette craving, as indicated, for example, by the failure of transdermal nicotine delivery patches or other nicotine replacement therapies to have a dramatic effect on smoking cessation success rates. Nicotine-free cigarettes can reduce cigarette craving symptoms, but they do not represent an alternative for use in environments where smoking is prohibited. It has been suggested that sensory effects of smoke inhalation, and to some extent, the simple motor effects of smoking behavior, may help to alleviate craving.
Habituation to tactile and kinesthetic aspects of handling and smoking a cigarette contributes to reinforcement of smoking behavior, as do the organoleptic qualities of cigarette smoke, the taste and other sensations in the mouth, throat and respiratory tract. Sensory aspects of smoking contribute to smoking behavior and relief of cigarette craving both through conditioned or learned association with nicotine delivery, but also through direct “hard-wired” autonomic and sensory-metabolic reflexes independent of nicotine entry into the brain. In particular, the characteristic airway sensation caused by inhaled tobacco smoke (sometimes referred to as “throat scratch,” “throat impact” or “throat hit”) is reported as a significant component of smoking satisfaction and especially of relief of acute cigarette craving. Isolated reduction of throat sensations with local anesthetics reduce the relief of smoking craving induced by nicotine-containing cigarette smoke; conversely, maintenance of throat scratch while disabling olfaction and oral taste sensation with an anesthetic mouthwash can alleviate the negative affect associated with cigarette craving. The “throat scratch” can affect perceived taste qualities and more subtle throat and airway autonomic sensory nerve stimulation, which can have effects beyond taste sensations. The airway sensations of inhaled cigarette smoke involve activation of receptors on sensory nerve endings by nicotine, other smoke components, as well as high temperatures of smoke.
An aerosol of citric acid or ascorbic acid has been reported to reduce cigarette craving symptoms via irritation of the throat. However, the airway sensations elicited by aerosols of these nonvolatile acids were accompanied by the sour taste sensations not associated with smoking tobacco and required generation of an aqueous aerosol by using a device that did not resemble a cigarette.
Inhalation of vapor from black pepper oil from a plastic cigarette-like device has been reported to reduce cigarette smoke craving. Some cigarette substitutes that simulate some features of the smoking experience, while acting as non-pyrolytic nicotine delivery devices, have also been described. Other such substitutes have been described which intend to reduce cigarette craving without delivering nicotine. Electrical devices for creating a vapor simulating tobacco smoke have also been described which typically involve heating a solution of nicotine and flavor agents dissolved in propylene glycol or glycerol to produce a smoke-like aerosol that delivers flavorings and nicotine in solvent droplets. Some vaporizing devices are shaped like a cigarette, including a battery, vaporizing chamber and a reservoir for liquid, which can be held in a porous substrate.
However, the devices described above fail to provide a non-combustible, non-electric cigarette substitute that adequately mimics tactile, kinesthetic, organoleptic and/or chemosensory qualities of cigarettes and cigarette smoking for relieving negative affect or mood associated with cigarette craving at times when smoking is not possible or for use in supporting smoking cessation.